Among agricultural crops, the same crops are continuously cultivated in the same agricultural field in the facility cultivation of fruit vegetables, and flowers and ornamental plants. Therefore, disease-causing bacteria and Nematode adapted in the proximity to soil and the root areas of crops become to grow at a high concentration in those areas. And they invade to the root tissues of the crops resulting in generating root rot and root nodules, moreover they invade to the vessels of the crops and may lead to generate plant diseases on the parts of the plants above the ground. As a result, the growth of crops delays, and the yield and quality of the crops decrease having serious economical damage. Therefore, soil fumigants and pesticides have been using to control soilborne pathogens and harmful pests in soil.
Chloropicrin shows an insecticide-fungicide action, and has been widely used as a soil fumigant. It is a water immiscible liquid and volatile with odor. When a reagent is applied to treat the soil, a single-purpose disinfection apparatus for the soil is used by a method of infusing 2 to 3 mL of the reagent to the soil about 15 cm in deep and 30 cm intervals followed by coating the surface of the soil with coating materials. Since this method requires the cumbersome procedure of implanting pesticides into the ground, there was a demand of an easy-to-use and efficient application method. To respond to this requirement, according to Patent Document 1, a pesticide emulsion comprising chloropicrin in addition to surfactant was developed and the emulsion could be mixed with water and applied for spraying. Moreover, Patent Document 2 disclosed a simple-to-use and effective way to achieve insect pest control, in which pesticide emulsion comprising chloropicrin in addition to a surfactant was applied to treat the soils through drip irrigation tubes and spraying it with a liquid fertilizer mixer while diluting pesticide emulsion with water after installing the drip irrigation tubes on the surface of the soil followed by covering it with coating materials.
It has been reported that chloropicrin is applied by mixing it with an organic phosphorous pesticide in order to compensate the efficacy of insect pest control of chloropicrin, or to improve the pest control effect of soil. For example, a fumigant comprising a mixture of chloropicrin and diazinon is disclosed in Patent Document 3 showing improving the residual efficacy of insect pest control of diazinon. Moreover, Patent Document 4 describes that the mixed composition comprising chloropicrin and propetamphos or fosthiazate can simultaneously achieve insecticidal-bactericidal effect in soil and pest control effect on harmful pests growing aboveground. Since the mixed use of chloropicrin along with organic phosphorous pesticide is a drug formulation that can achieve excellent and efficient insect pest control of harmful pests, there is a demand for the development of a mixed preparation with easy-to-use.
On the contrary, several reports are published that the development of mixed preparations of organic phosphorous pesticides with several pesticides for the purpose of compensating and enforcing the efficacy of killing pests. Patent Document 5 discloses a mixed composition of organic phosphorus pesticide-nematicide comprising an organic phosphorus-type nematicides selected from fosthiazate, imicyafos, or cadusafos, and an organic phosphorus-type pesticide as active ingredients.
However, chloropicrin has a physical property that gradually releases its acid component during the storage so that has concern about acidolysis of components in the mixed preparation by mixed use with other active ingredients in other pesticides. Especially, the organic phosphorous pesticide has a physical property of acidolysis and hydrolysis. Therefore, it was difficult to guarantee long-term storage stability for a mixed pesticide preparation in a metal container that filled with the mixed agrochemical emulsion composition comprising chloropicrin and an organic phosphorous pesticide.